This research proposes to analyse, from the Brazilian legal order, the level of linking the Public Administration owns in the execution of actions, informed in the public budget, that concretize fundamental social rights of prestational nature. The public budget has progressed from a way of political control of the Legislative Power over the Executive Power to a democratically decided instrument of planning and programming of the State’s financial actions. The 21st Century consecrates a new hermeneutic process that overcomes the classic positivist model. This post positivism presents its innovations: the acknowledgement of the constitutional norms of fundamental rights’ normative force, including in the prestational social ones, and the prestige of the constitutionally consecrated values. The 1988 Constitution imposes to the public agent the duty of presenting a clear and transparent conduct, owing at all times reverence to society, reporting his acts and justifying his attitudes, including the discretionary and omissive ones. In this context, the Brazilian legal order – in particular, the Constitution - imposes the recognition of the existence of an implicit norm of an imposing budget in the concretization of fundamental social rights. In reason of each concrete case circumstances, its application happens as a norm-rule or norm-principle. At first, the budget must be executed in full form by the Administration. The reasonability of conduct and of motivations expressed by the Administration will always be susceptible to measurement by the Judicial Power, by society and by other control organs.